Honeycomb Core Poisson Ratio 1

[sarclee]

Hi, I would like to ask if I use lamination for calculating sandwich properties, what Poisson ratio should I use for the aluminium core?

I usually assume 10 for nomex... But I'm not sure... Thanks!

 

[WKTaylor]

FYI my practical experience with aluminum honeycomb panels/part-Assys.

I usually see panels/parts designed to withstand ultimate design + a-lot... then typically fail suddenly by localized crushing/crippling/delaminating/core-shearing.

This design practice is simply because of practical material thickness [face-sheets, honeycomb foil/hex-size], cutting/machining, adhesive edging/close-out and a variety of 'penetrations requirements' [thru fasteners, cutouts, etc],etc, etc. The difference between a perfect min-weight design and a practical slightly heavier design is a few percent... while added 'robustness' helps endure 'wild-card' long-term environmental effects [way too many possibilities to discuss here].

Be aware of: (a) damage at/along edges/closeouts, and a other mountings [an amazing variety of reasons]; Or (b) moisture intrusion [or other fluids such as oil, fuel, etc] ... leading to internal corrosion and/or lowered adhesive glass transition temps; or (c) extreme point [puncture] loads or added mass; (d) electrical bonding/grounding requirements; (e) extreme temperature variations/requirements [Example: my jet was designed of -65F to +160F... but has endured actual conditions of -100F to +190F].

Regards, Wil Taylor
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[rb1957]

I would watch your units ... mixing meters and mm, Pa and MPa.

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